“Dragnet” is held in low regard these days, thanks to people who saw the TV show in reruns and could not figure out how anyone could be that square. It didn’t help that the production values gave everything a spartan appearance - cheap, you might say. The lighting style is dated. The message shows were hilariously didactic. Friday seemed abnormally single. His partner, Bill Gannon, was comic relief, but tiresome in large doses. The shows consisted of guys standing around and writing things down.
Put it all on radio, and it’s different. It was different than anything else at the time. Webb wanted a cop show that was realistic and authentic, down to the number of footsteps you’d hear going from the elevator in the cop shop to the door. They used jargon without explaining it - Friday would say he ran the name through “RNI,” but they never told you what that was. (“Records and Information.”) Conversation was often banal; ordinary boring people were just that. It broke all the rules of radio.
The show didn’t just revolutionize cop dramas, it revolutionized radio: “Gunsmoke” was an attempt to do a Western version, and ended up influencing two other great radio westerns. But that’s another page.
As Wikipedia notes:
Throughout the series' radio years, many episodes offer interesting glimpses of pre-renewal Downtown L.A., still full of working class residents and the cheap bars, cafes, hotels and boarding houses which served them.
The entire series is available, for free, here at archive.org.
When you listen to the shows, you may realize something about the TV series. Every scene ends with the baleful woodwinds of Walter Schumann, transitioning to the next scene. Webb kept them in for the TV version - but because it was TV, not radio, they had to show something.
That's why every scene in Dragnet ended with everyone standing there doing nothing, looking confused, or nodding.